Calibration of Barlat Yld2004-18P yield function using CPFEM and 3D RVE for the simulation of single point incremental forming (SPIF) of 7075-O aluminum sheet. (September 2018)

• Record Type: Journal Article
• Authors: Esmaeilpour, Rasoul; Kim, Hyunki; Park, Taejoon; Pourboghrat, Farhang; Xu, Zeren; Mohammed, Bassam; Abu-Farha, Fadi
• Is Part Of: International journal of mechanical sciences. Volume 145(2018)
• Page Start: 24
• Page End: 41
• Publication Date: 2018-09
• Subjects: 3D RVE -- Representative volume element -- Virtual experiment -- Crystal plasticity -- 3D stress state yield function -- Yld2004 -- Material anisotropy -- AA7075-O -- Single-point incremental forming (SPIF); Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2018.05.015
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: Virtual experiments were performed using three dimensional (3D) representative volume elements (RVEs) created from Electron Backscattered Diffraction (EBSD) images. By applying the crystal plasticity (CP) material model to these 3D RVEs, it was possible to generate out-of-plane stresses required for the calibration of the Yld2004-18p yield function. Given the significance of through-the-thickness shear in SPIF, and that aluminum 7075 is anisotropic, Yld2004-18p was used as a non-quadratic anisotropic 3D yield function for the finite element simulation of incremental sheet forming. Anisotropy behavior of this alloy was characterized using Yld2004-18p and also Hill's 1948. Yld2004-18p and Hill's 1948 were used to simulate the single point incremental forming (SPIF) of 7075-O aluminum alloy sheet. A detailed comparison of the two yield functions' predictions were made with respect to different parameters. Abstract: In conventional sheet metal forming processes, such as stamping, application of a two-dimensional (2D) plane stress yield function is sufficient as the out-of-plane stresses (σ zz, σ xz, σ yz ) are negligible and the deformation occurs under plane stress condition. However, in incremental sheet forming (ISF) processes, significant through-the-thickness shears necessitates the use of a three-dimensional (3D) yield function to account for out-of-plane stress components. However, to calibrate the parameters of the non-quadratic anisotropic 3D yield function Yld2004-18p, out-of-plane normal and shear stresses are needed which are very difficult to obtain experimentally. In this study, the out-of-plane stresses were found using a three-dimensional (3D) representative volume element (RVE) developed from Electron Backscattered Diffraction (EBSD) images. By applying the crystal plasticity (CP) material model to these 3D RVEs, it was possible to perform computational experiments to generate the out-of-plane stresses required for the calibration of the Yld2004-18p yield function. To simulate the single point incremental forming (SPIF) of 7075-O aluminum alloy sheet, two different yield functions namely; Hill's 1948 and Yld2004-18p were used. A detailed comparison of the two yield functions' predictions was made with respect to different parameters, such as the tool force and moment, part thickness, development of stress and strain tensor components, and effective plastic strain distribution. Graphical abstract: Image, graphical abstract